But he will be on the first tee on Thursday alongside Henrik Stenson and Adam Scott, who could replace Woods at the top of the world rankings with victory in the second WGC event of the year.

"I feel better. I feel good," Woods said. "It has been a long couple of days of just treatment non-stop, trying to get it to calm down and trying to get everything firing in the proper sequence. It feels good.

"My treatments have been fantastic. It's annoying to be poked and prodded all the time but it has gotten me to the point where I can do this and this week I will be able to hit full shots."

Woods was also hampered by back spasms during the FedExCup play-offs last season, and he added: "It comes and goes. I thought I could play through it. I couldn't. Sometimes it gets better. Others, I just deal with it."

Masters motivation

The 38-year-old is determined to be at peak fitness for the Masters next month as he bids for his first win at Augusta since 2005.

"I want to be strong and fit and healthy to play that golf course and give it my best," he said. "We're taking a really good look at it and trying to come up with a good plan to play that course and trying to win my fifth green jacket."

His withdrawal at PGA National on Sunday was his fourth in five years due to injury, and he conceded that he takes longer to recover as he approaches 40.

"It's the nature of a repetitive sport. We do the same motion. You have repetitive injuries," Woods said.

"Most of my injuries are that. The nature of why we lift, why we work out, is to stay out here. I've learned as I get older that I don't heal as fast, I don't bounce back like I used to. It's just not that way anymore.

"A bad back is something that is no joke. When I had my knee injuries it was always after impact. I can do my job and deliver the club. It's just going to hurt like hell afterwards. I did that for years.

"But a back, with that motion, there are some things you just can't do. This affects downswing, backswing, follow through. I can handle pain but I just couldn't move out there. I couldn't twist."

Scott targets top spot

Scott needs to win the event and hope Woods finishes outside the top 10 if he wants to become the first Australian to top the world rankings since Greg Norman, who held it for 331 weeks.

"I've said the whole time I wouldn't really think about it when it came to this and it's impossible not to think about it," said the 33-year-old Masters champion.

"It would be a dream come true to make it to that point but it's not necessarily probable either.

"If you look at stats and numbers there's no reason why I'm just going to roll out and win this week but there's great motivation for me to do that.

"I don't know how Tiger feels about it but it's obviously a position he's pretty comfortable with for a long time throughout his career, and I can assure you from knowing him just a little bit it's a position he probably wouldn't want to give up.

"So I don't know that we're going to be trying to play each other head-to-head, because we know this field is a lot bigger than the two of us."